The Word Virginitas Applied to Married Women

Mighty Juno
is her brother's appointed, established spouse:
then why is the sister and marriage partner
of Augustus driven from her father's palace?
What help to her is her unstained goodness,
her deified father,
her maidenhood, her chastity?

Nero married Octavia in 53, and the dramatic date of the play is 62. The word virginitas seems odd applied to a woman married for so long. Nero accused her of being sterile (Tacitus, Annals 14.60.1: sterilem dictitans), which implies that the attempt to conceive was made. Fitch, p. 564, n. 32 (on Octavia, line 537), tries to argue around this:

According to the historian Tacitus, the justification given by Nero for his divorce of Octavia was her alleged sterility. But the play strongly hints that Octavia had refused sexual relations with Nero (e.g. line 287).